Industrial waste water, for instance from winery or olive oil production, contains a wide range of organic matter. Such waste water requires treatment according to Chemical Oxygen Demand (COD) level as well as treatment to prevent odour and H2S emissions. Although the availability of organic matter for biological processes is limited the concentration of organic compounds remains too high to use a pure chemical oxidizer system for pre-treatment efficiently.
State of the art for the treatment of this kind of waste water is the application of heavy oxidizers, like hydroxyl or hydrogen peroxide, in combination with a catalyst, for instance titanium dioxide. At the same time the chemical oxidizer spent is also used to oxidize matter that is easily biological degradable. Hence the chemical oxidizer is used inefficiently since parts of the oxidizer are used to oxidize biological degradable matter. On the other hand, treatment by pure biological steps is generally not able to have an effect on heavy degradable substances like oily or aromatic substances. Therefore a single kind of treatment—whether chemical or biological—remains inefficient or ineffective.
Additionally industrial processes often follow patterns on one hand and can change production on the other hand spontaneously. For that reason most systems run either on 100% treatment capacity or in manual mode. This kind of treatment may be successful most of the time, but also has unfortunate side effects. At peak emissions odour and H2S as well as COD in the waste water will not be treated sufficiently, and under low emission conditions unnecessary treatment with overdosed chemicals occur. This cause discomfort and contamination under peak emission and additional cost and emission of overdosed chemicals under low emission conditions.
Current standard comprises collection data like measurement results and process parameters and transfer of the data to central database systems which can present data to the user through a network like internet. Current standard may also comprise feedback dosage from a remote measurement probe to a dosing controller via radio modem. Current standard also provide manual control of treatment and results by the operator. Included in current standard is also the possibility to change treatment parameters manually in accordance with operators demand. It would be desirable to use treatment processes for industrial waste water that can handle easily degradable organic matter in a biological treatment step and biological hardly degradable matter in a chemical treatment step. The system as such should be adaptive using process parameters like conductivity and/or hydrogen sulphide (H2S) to adjust the dosages not only according to pre-set parameters but also according to production patterns and dynamic demands. Additionally the interaction with the operator should be used to prepare the system for unexpected system changes. Monitoring and adjusting dosage control should be done using an interactive interface, to create a simple, user friendly operating process.
From prior art several methods for the treatment of industrial waste water are known.
JP 10-015591 discloses a process wherein the first step in the waste water treatment is ammonia stripping and a biological treatment wherein nitrogen is processed biologically followed by a coagulation sedimentation stage and finally a chemical oxidation step. In contrast to the present invention the process is focussing on BOD degradation and not the biological harder degradable matter (COD-BOD).
US 2006/0196828 and US 2007/0034566 concern methods for treatment of oxidant waste streams, wherein domestic waste water is mixed with the oxidant stream before treatment in a bioreactor. The processes disclosed mainly concerns an oxidizer unit in front of the biological treatment. This unfortunately leads to partly degraded matter, such as aromatic compounds e.g. benzene, that cannot be treated biologically either. Thus efficiency as well as the effectiveness in total might be reduced. The present invention uses the chemical oxidizer in a second treatment step concerned with non-biological degradable matter.
JP 58-92498 discloses a method wherein waste water containing ammonia and BOD components is mixed with recycled sludge and a nitrate solution and subjected to biological treatment. Today this is a commonly used process, called the denitrification step. In the present invention the nitrogen addition is used to stimulate anaerobic conditions in the first treatment step.